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Active ingredients and Inert ingredients
Aug 09, 2018

Active ingredients

The active ingredient or constituent is the part of the formulation that is responsible for the pesticide’s biological activity, e.g. in an insecticide it is the part that kills the insect and in a herbicide the part that kills the weed. The name of the active ingredient and its concentration are given on the front panel of the label under the product name. For example, the herbicide Roundup contains 360 g/L of the active ingredient glyphosate. This means that in 1 L of Roundup product or concentrate, just over one third (360 g) is the active ingredient glyphosate. There are many herbicides which contain glyphosate. While Roundup was the original product, there are now many brands with names like Cleanup, Credit, Gladiator, Ken-Up, Razor, Touchdown, Wipe-Out, and Zero. Because there is a host of product names, all with the same active ingredient and similar use patterns, it is often more helpful to refer to glyphosate products in general than to list all the different brands. As well as the name of the active ingredient, the concentration is also important. In the case of toxic insecticides, the proportion of the active ingredient will affect the poison scheduling. For example, the highly toxic insecticide parathion is a schedule 6 poison if the concentration of the active ingredient is 45% or less of the total formulation such as the product Penncap-M which contains 240 g/L parathion. On the other hand, the product Folidol M500 which contains 500 g/L parathion, is a schedule 7 poison. The higher poison scheduling in this case reflects the increased risk of acute poisoning due to the greater proportion of the active ingredient, parathion, in the formulation.

Inert ingredients

So-called inert or ‘inactive’ ingredients are solvents and carriers that deliver the active ingredient to the target – pest, weed or disease. If the inert ingredient is a scheduled poison or hazardous substance, i.e. harmful to human health, it should be listed on the front panel of the label under the active ingredient but this is not always the case. For example, the insecticide Fastac Duo contains 100 g/L of the active ingredient alpha-cypermethrin and 751 g/L of the solvent xylene. Both the active ingredient and the carrier are poisons in their own right. Further information about other parts of the formulation can sometimes be found in the MSDS under the section on ‘Composition/information on ingredients’ in the front of the MSDS. however, instead of specific chemical names, vague general chemical names are often given like ‘liquid hydrocarbons’, ‘hydrocarbon solvent’, ‘emulsifiers’ and ‘surfactants’. Other MSDSs are even less helpful, merely listing ‘other ingredients (non-hazardous)’ or ‘inerts (non-hazardous)’. If a formulation includes a significant amount of organic solvents or hydrocarbons as a carrier, it will usually be classified as a Class 3 Dangerous Good (DG), indicating a flammability risk in storage. Sometimes the presence of hydrocarbons will be indicated on the front panel of the label under the active ingredient. If not, it will be listed in the MSDS. In any case, the label will carry the Class 3 diamond and the full DG information will be included in the MSDS in the section on ‘Transport information’ towards the end of the MSDS.